Posts

Vittorio Gallo

Special issue of “Neurochemical Research” honors Vittorio Gallo, Ph.D.

Vittorio Gallo

Investigators from around the world penned manuscripts that were assembled in a special issue of “Neurochemical Research” that honors Vittorio Gallo, Ph.D., for his leadership in the field of neural development and regeneration.

At a pivotal moment early in his career, Vittorio Gallo, Ph.D., was accepted to work with Professor Giulio Levi at the Institute for Cell Biology in Rome, a position that leveraged courses Gallo had taken in neurobiology and neurochemistry, and allowed him to work in the top research institute in Italy directed by the Nobel laureate, Professor Rita Levi-Montalcini.

For four years as a student and later as Levi’s collaborator, Gallo focused on amino acid neurotransmitters in the brain and mechanisms of glutamate and GABA release from nerve terminals. Those early years cemented a research focus on glutamate neurotransmission that would lead to a number of pivotal publications and research collaborations that have spanned decades.

Now, investigators from around the world who have worked most closely with Gallo penned tributes in the form of manuscripts that were assembled in a special issue of “Neurochemical Research” that honors Gallo “for his contributions to our understanding of glutamatergic and GABAergic transmission during brain development and to his leadership in the field of neural development and regeneration,” writes guest editor Arne Schousboe, of the University of Copenhagen in Denmark.

Dr. Gallo as a grad student

Vittorio Gallo, Ph.D. as a 21-year-old mustachioed graduate student.

“In spite of news headlines about competition in research and many of the negative things we hear about the research world, this shows that research is also able to create a community around us,” says Gallo, chief research officer at Children’s National Hospital and scientific director for the Children’s National Research Institute.

As just one example, he first met Schousboe 44 years ago when Gallo was a 21-year-old mustachioed graduate student.

“Research can really create a sense of community that we carry on from the time we are in training, nurture as we meet our colleagues at periodic conferences, and continue up to the present. Creating community is bi-directional: influencing people and being influenced by people. People were willing to contribute these 17 articles because they value me,” Gallo says. “This is a lot of work for the editor and the people who prepared papers for this special issue.”

In addition to Gallo publishing more than 140 peer-reviewed papers, 30 review articles and book chapters, Schousboe notes a number of Gallo’s accomplishments, including:

  • He helped to develop the cerebellar granule cell cultures as a model system to study how electrical activity and voltage-dependent calcium channels modulate granule neuron development and glutamate release.
  • He developed a biochemical/neuropharmacological assay to monitor the effects of GABA receptor modulators on the activity of GABA chloride channels in living neurons.
  • He and Maria Usowicz used patch-clamp recording and single channel analysis to demonstrate for the first time that astrocytes express glutamate-activated channels that display functional properties similar to neuronal counterparts.
  • He characterized one of the spliced isoforms of the AMPA receptor subunit gene Gria4 and demonstrated that this isoform was highly expressed in the cerebellum.
  • He and his Children’s National colleagues demonstrated that glutamate and GABA regulate oligodendrocyte progenitor cell proliferation and differentiation.
Purkinje cells

Purkinje cells are large neurons located in the cerebellum that are elaborately branched like interlocking tree limbs and represent the only source of output for the entire cerebellar cortex.

Even the image selected to grace the special issue’s cover continues the theme of continuity and leaving behind a legacy. That image of Purkinje cells was created by a young scientist who works in Gallo’s lab, Aaron Sathyanesan, Ph.D. Gallo began his career working on the cerebellum – a region of the brain important for motor control – and now studies with a team of scientists and clinician-scientists Purkinje cells’ role in locomotor adaptive behavior and how that is disrupted after neonatal brain injury.

“These cells are the main players in cerebellar circuitry,” Gallo says. “It’s a meaningful image because goes back to my roots as a graduate student and is also an image that someone produced in my lab early in his career. It’s very meaningful to me that Aaron agreed to provide this image for the cover of the special issue.”

Catherine Limperopoulos

Stressful pregnancies can leave fingerprint on fetal brain

Catherine Limperopoulos

“We were alarmed by the high percentage of pregnant women with a diagnosis of a major fetal heart problem who tested positive for stress, anxiety and depression,” says Catherine Limperopoulos, Ph.D., director of the Center for the Developing Brain at Children’s National and the study’s corresponding author.

When a diagnosis of fetal congenital heart disease causes pregnant moms to test positive for stress, anxiety and depression, powerful imaging can detect impaired development in key fetal brain regions, according to Children’s National Hospital research published online Jan. 13, 2020, in JAMA Pediatrics.

While additional research is needed, the Children’s National study authors say their unprecedented findings underscore the need for universal screening for psychological distress as a routine part of prenatal care and taking other steps to support stressed-out pregnant women and safeguard their newborns’ developing brains.

“We were alarmed by the high percentage of pregnant women with a diagnosis of a major fetal heart problem who tested positive for stress, anxiety and depression,” says Catherine Limperopoulos, Ph.D., director of the Center for the Developing Brain at Children’s National and the study’s corresponding author. “Equally concerning is how prevalent psychological distress is among pregnant women generally. We report for the first time that this challenging prenatal environment impairs regions of the fetal brain that play a major role in learning, memory, coordination, and social and behavioral development, making it all the more important for us to identify these women early during pregnancy to intervene,” Limperopoulos adds.

Congenital heart disease (CHD), structural problems with the heart, is the most common birth defect. Still, it remains unclear how exposure to maternal stress impacts brain development in fetuses with CHD.

The multidisciplinary study team enrolled 48 women whose unborn fetuses had been diagnosed with CHD and 92 healthy women with uncomplicated pregnancies. Using validated screening tools, they found:

  • 65% of pregnant women expecting a baby with CHD tested positive for stress
  • 27% of women with uncomplicated pregnancies tested positive for stress
  • 44% of pregnant women expecting a baby with CHD tested positive for anxiety
  • 26% of women with uncomplicated pregnancies tested positive for anxiety
  • 29% of pregnant women expecting a baby with CHD tested positive for depression and
  • 9% women with uncomplicated pregnancies tested positive for depression

All told, they performed 223 fetal magnetic resonance imaging sessions for these 140 fetuses between 21 and 40 weeks of gestation. They measured brain volume in cubic centimeters for the total brain as well as volumetric measurements for key regions such as the cerebrum, cerebellum, brainstem, and left and right hippocampus.

Maternal stress and anxiety in the second trimester were associated with smaller left hippocampi and smaller cerebellums only in pregnancies affected by fetal CHD. What’s more, specific regions — the hippocampus head and body and the left cerebellar lobe – were more susceptible to stunted growth. The hippocampus is key to memory and learning, while the cerebellum controls motor coordination and plays a role in social and behavioral development.

The hippocampus is a brain structure that is known to be very sensitive to stress. The timing of the CHD diagnosis may have occurred at a particularly vulnerable time for the developing fetal cerebellum, which grows faster than any other brain structure in the second half of gestation, particularly in the third trimester.

“None of these women had been screened for prenatal depression or anxiety. None of them were taking medications. And none of them had received mental health interventions. In the group of women contending with fetal CHD, 81% had attended college and 75% had professional educations, so this does not appear to be an issue of insufficient resources,” Limperopoulos adds. “It’s critical that we routinely to do these screenings and provide pregnant women with access to interventions to lower their stress levels. Working with our community partners, Children’s National is doing just that to help reduce toxic prenatal stress for both the health of the mother and for the future newborns. We hope this becomes standard practice elsewhere.”

Adds Yao Wu, Ph.D., a research associate working with Limperopoulos at Children’s National and the study’s lead author: “Our next goal is exploring effective prenatal cognitive behavioral interventions to reduce psychological distress felt by pregnant women and improve neurodevelopment in babies with CHD.”

In addition to Limperopoulos and Wu , Children’s National study co-authors include Kushal Kapse, MS, staff engineer; Marni Jacobs, Ph.D., biostatistician; Nickie Niforatos-Andescavage, M.D., neonatologist; Mary T. Donofrio, M.D., director, Fetal Heart Program; Anita Krishnan, M.D., associate director, echocardiography; Gilbert Vezina, M.D., director, Neuroradiology Program; David Wessel, M.D., Executive Vice President and Chief Medical Officer; and Adré  J. du Plessis, M.B.Ch.B., director, Fetal Medicine Institute. Jessica Lynn Quistorff, MPH, Catherine Lopez, MS, and Kathryn Lee Bannantine, BSN, assisted with subject recruitment and study coordination.

Financial support for the research described in this post was provided by the National Institutes of Health under grant No. R01 HL116585-01 and the Thrasher Research Fund under Early Career award No. 14764.

allopregnanolone molecule

Autism spectrum disorder risk linked to insufficient placental steroid

allopregnanolone molecule

A study led by Children’s National Hospital and presented during Neuroscience 2019 finds that loss of allopregnanolone, a key hormone supplied by the placenta, leads to long-term structural alterations of the cerebellum – a brain region essential for smooth motor coordination, balance and social cognition – and increases the risk of developing autism.

An experimental model study suggests that allopregnanolone, one of many hormones produced by the placenta during pregnancy, is so essential to normal fetal brain development that when provision of that hormone decreases – as occurs with premature birth – offspring are more likely to develop autism-like behaviors, a Children’s National Hospital research team reports at the Neuroscience 2019 annual meeting.

“To our knowledge, no other research team has studied how placental allopregnanolone (ALLO) contributes to brain development and long-term behaviors,” says Claire-Marie Vacher, Ph.D., lead author. “Our study finds that targeted loss of ALLO in the womb leads to long-term structural alterations of the cerebellum – a brain region that is essential for motor coordination, balance and social cognition ­– and increases the risk of developing autism,” Vacher says.

According to the Centers for Disease Control and Prevention, about 1 in 10 infants is born preterm, before 37 weeks gestation; and 1 in 59 children has autism spectrum disorder.

In addition to presenting the abstract, on Monday, Oct. 21, Anna Penn, M.D., Ph.D., the abstract’s senior author, will discuss the research with reporters during a Neuroscience 2019 news conference. This Children’s National abstract is among 14,000 abstracts submitted for the meeting, the world’s largest source of emerging news about brain science and health.

ALLO production by the placenta rises in the second trimester of pregnancy, and levels of the neurosteroid peak as fetuses approach full term.

To investigate what happens when ALLO supplies are disrupted, a research team led by Children’s National created a novel transgenic preclinical model in which they deleted a gene essential in ALLO synthesis. When production of ALLO in the placentas of these experimental models declines, offspring had permanent neurodevelopmental changes in a sex- and region-specific manner.

“From a structural perspective, the most pronounced cerebellar abnormalities appeared in the cerebellum’s white matter,” Vacher adds. “We found increased thickness of the myelin, a lipid-rich insulating layer that protects nerve fibers. From a behavioral perspective, male offspring whose ALLO supply was abruptly reduced exhibited increased repetitive behavior and sociability deficits – two hallmarks in humans of autism spectrum disorder.”

On a positive note, providing a single ALLO injection during pregnancy was enough to avert both the cerebellar abnormalities and the aberrant social behaviors.

The research team is now launching a new area of research focus they call “neuroplacentology” to better understand the role of placenta function on fetal and newborn brain development.

“Our team’s data provide exciting new evidence that underscores the importance of placental hormones on shaping and programming the developing fetal brain,” Vacher notes.

  • Neuroscience 2019 presentation
    Sunday, Oct. 20, 9:30 a.m. (CDT)
    “Preterm ASD risk linked to cerebellar white matter changes”
    Claire-Marie Vacher, lead author; Sonia Sebaoui, co-author; Helene Lacaille, co-author; Jackie Salzbank, co-author; Jiaqi O’Reilly, co-author; Diana Bakalar, co-author; Panagiotis Kratimenos, M.D., neonatologist and co-author; and Anna Penn, M.D., clinical neonatologist and developmental neuroscientist and senior author.
illustration of brain showing cerebellum

Focusing on the “little brain” to rescue cognition

illustration of brain showing cerebellum

Research faculty at Children’s National in Washington, D.C., with colleagues recently published a review article in Nature Reviews Neuroscience that covers the latest research about how abnormal development of the cerebellum leads to a variety of neurodevelopmental disorders.

Cerebellum translates as “little brain” in Latin. This piece of anatomy – that appears almost separate from the rest of the brain, tucked under the two cerebral hemispheres – long has been known to play a pivotal role in voluntary motor functions, such as walking or reaching for objects, as well as involuntary ones, such as maintaining posture.

But more recently, says Aaron Sathyanesan, Ph.D., a postdoctoral research fellow at the Children’s Research Institute, the research arm of Children’s National  in Washington, D.C., researchers have discovered that the cerebellum is also critically important for a variety of non-motor functions, including cognition and emotion.

Sathyanesan, who studies this brain region in the laboratory of Vittorio Gallo, Ph.D., Chief Research Officer at Children’s National and scientific director of the Children’s Research Institute, recently published a review article with colleagues in Nature Reviews Neuroscience covering the latest research about how altered development of the cerebellum contributes to a variety of neurodevelopmental disorders.

These disorders, he explains, are marked by problems in the nervous system that arise while it’s maturing, leading to effects on emotion, learning ability, self-control, or memory, or any combination of these. They include diagnoses as diverse as intellectual disability, autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder and Down syndrome.

“One reason why the cerebellum might be critically involved in each of these disorders,” Sathyanesan says, “is because its developmental trajectory takes so long.”

Unlike other brain structures, which have relatively short windows of development spanning weeks or months, the principal cells of the cerebellum – known as Purkinje cells – start to differentiate from stem cell precursors at the beginning of the seventh gestational week, with new cells continuing to appear until babies are nearly one year old.  In contrast, cells in the neocortex, a part of the brain involved in higher-order brain functions such as cognition, sensory perception and language is mostly finished forming while fetuses are still gestating in the womb.

This long window for maturation allows the cerebellum to make connections with other regions throughout the brain, such as extensive connections with the cerebral cortex, the outer layer of the cerebrum that plays a key role in perception, attention, awareness, thought, memory, language and consciousness. It also allows ample time for things to go wrong.

“Together,” Sathyanesan says, “these two characteristics are at the root of the cerebellum’s involvement in a host of neurodevelopmental disorders.”

For example, the review article notes, researchers have discovered both structural and functional abnormalities in the cerebellums of patients with ASD. Functional magnetic resonance imaging (MRI), an imaging technique that measures activity in different parts of the brain, suggests that significant differences exist between connectivity between the cerebellum and cortex in people with ASD compared with neurotypical individuals. Differences in cerebellar connectivity are also evident in resting-state functional connectivity MRI, an imaging technique that measures brain activity in subjects when they are not performing a specific task. Some of these differences appear to involve patterns of overconnectivity to different brain regions, explains Sathyanesan; other differences suggest that the cerebellums of patients with ASD don’t have enough connections to other brain regions.

These findings could clarify research from Children’s National and elsewhere that has shown that babies born prematurely often sustain cerebellar injuries due to multiple hits, including a lack of oxygen supplied by infants’ immature lungs, he adds. Besides having a sibling with ASD, premature birth is the most prevalent risk factor for an ASD diagnosis.

The review also notes that researchers have discovered structural changes in the cerebellums of patients with Down syndrome, who tend to have smaller cerebellar volumes than neurotypical individuals. Experimental models of this trisomy recapitulate this difference, along with abnormal connectivity to the cerebral cortex and other brain regions.

Although the cerebellum is a pivotal contributor toward these conditions, Sathyanesan says, learning more about this brain region helps make it an important target for treating these neurodevelopmental disorders. For example, he says, researchers are investigating whether problems with the cerebellum and abnormal connectivity could be lessened through a non-invasive form of brain stimulation called transcranial direct current stimulation or an invasive one known as deep brain stimulation. Similarly, a variety of existing pharmaceuticals or new ones in development could modify the cerebellum’s biochemistry and, consequently, its function.

“If we can rescue the cerebellum’s normal activity in these disorders, we may be able to alleviate the problems with cognition that pervade them all,” he says.

In addition to Sathyanesan and Senior Author Gallo, Children’s National study co-authors include Joseph Scafidi, D.O., neonatal neurologist; Joy Zhou and Roy V. Sillitoe, Baylor College of Medicine; and Detlef H. Heck, of University of Tennessee Health Science Center.

Financial support for research described in this post was provided by the National Institute of Neurological Disorders and Stroke under grant numbers 5R01NS099461, R01NS089664, R01NS100874, R01NS105138 and R37NS109478; the Hamill Foundation; the Baylor College of Medicine Intellectual and Developmental Disabilities Research Center under grant number U54HD083092; the University of Tennessee Health Science Center (UTHSC) Neuroscience Institute; the UTHSC Cornet Award; the National Institute of Mental Health under grant number R01MH112143; and the District of Columbia Intellectual and Developmental Disabilities Research Center under grant number U54 HD090257.

preterm brain scans

Early lipids in micropreemies’ diets can boost brain growth

preterm brain scans

Segmentation of a preterm brain T2-weighted MRI image at 30 gestational weeks [green=cortical grey matter; blue=white matter; grey=deep grey matter; cyan=lateral ventricle; purple=cerebellum; orange=brainstem; red=hippocampus; yellow=cerebrospinal fluid].

Dietary lipids, already an important source of energy for tiny preemies, also provide a much-needed brain boost by significantly increasing global brain volume as well as increasing volume in regions involved in motor activities and memory, according to research presented during the Pediatric Academic Societies 2019 Annual Meeting.

“Compared with macronutrients like carbohydrates and proteins, lipid intake during the first month of life is associated with increased overall and regional brain volume for micro-preemies,” says Catherine Limperopoulos, Ph.D., director of MRI Research of the Developing Brain at Children’s National and senior author. “Using non-invasive magnetic resonance imaging, we see increased volume in the cerebellum by 2 weeks of age. And at four weeks of life, lipids increase total brain volume and boost regional brain volume in the cerebellum, amygdala-hippocampus and brainstem.”

The cerebellum is involved in virtually all physical movement and enables coordination and balance. The amygdala processes and stores short-term memories. The hippocampus manages emotion and mood. And the brainstem acts like a router, passing messages from the brain to the rest of the body, as well as enabling essential functions like breathing, a steady heart rate and swallowing.

According to the Centers for Disease Control and Prevention, about 1 in 10 U.S. babies is born preterm, or before 37 weeks gestation. Regions of the brain that play vital roles in complex cognitive and motor activities experience exponential growth late in pregnancy, making the developing brains of preterm infants particularly vulnerable to injury and impaired growth.

Children’s research faculty examined the impact of lipid intake in the first month of life on brain volumes for very low birth weight infants, who weighed 1,500 grams or less at birth. These micro-preemies are especially vulnerable to growth failure and neurocognitive impairment after birth.

The team enrolled 68 micro-preemies who were 32 weeks gestational age and younger when they were admitted to Children’s neonatal intensive care unit during their first week of life. They measured cumulative macronutrients – carbohydrates, proteins, lipids and calories – consumed by these newborns at 2 and 4 weeks of life. Over years, Limperopoulos’ lab has amassed a large database of babies who were born full-term; this data provides unprecedented insights into normal brain development and will help to advance understanding of brain development in high-risk preterm infants.

“Even after controlling for average weight gain and other health conditions, lipid intake was positively associated with cerebellar and brainstem volumes in very low birthweight preterm infants,” adds Katherine M. Ottolini, the study’s lead author.

According to Limperopoulos, Children’s future research will examine the optimal timing and volume of lipids to boost neurodevelopment for micro-preemies.

Pediatric Academic Societies 2019 Annual Meeting presentation

  • “Early lipid intake improves brain growth in premature infants.”
    • Saturday, April 27, 2019, 1:15-2:30 p.m. (EST)

Katherine M. Ottolini, lead author; Nickie Andescavage, M.D., Attending, Neonatal-Perinatal Medicine and co-author; Kushal Kapse, research and development staff engineer and co-author; and Catherine Limperopoulos, Ph.D., director of MRI Research of the Developing Brain and senior author, all of Children’s National.